The benefits of glued laminated timber (glulam)

Geraldine Chua

This article is part of a series of engineered timber features looking at the advantages and possibilities of mass timber construction, as well as its growing uptake in the Australian building and construction industry.

Glued laminated timber, or glulam, is an engineered timber product manufactured by gluing together smaller pieces of stress graded and seasoned timber. The laminates are typically finger-jointed into continuous lengths, and available in both softwood and hardwood species.

Prior to gluing, the laminates are dressed to exact and uniform thickness. They are clamped together under constant pressure until the glue has cured, and before the members are planed, cut to exact size, and sometimes coated with a water repellent sealant.

Because glulam is made up of many laminates, strength-reducing characteristics are often absent or just confined to one laminate. As a result, the product is stronger than solid timber, and its strength and performance predictions are usually very reliable. The manufacturing process also allows for larger and longer members than would otherwise be possible with traditional solid sawn timber.

Originating in Germany around the 1900s, glulam was adopted by Australia in the 1950’s but has not reached the same level of popularity as in Europe and North America. According to the Glued Laminated Timber Association of Australia (GLTAA), the annual glulam consumption in Australia is approximately 30,000 cubic metres, which is only 0.6 per cent of our total timber consumption.

Glulam was used in the construction of Ipswich University. Image: GLTAA

Here, glulam is commonly used for beams in both structural and decorative applications. It has been likened to laminated veneer lumber (LVL) as they are both similar in strength, although glulam offers wider design possibilities because of its aesthetics and a higher level of finish quality. In general, glulam is also the more expensive product between the two, but remains cost competitive with structural steel.

The length and shape of glulam sections is limited only by manufacturing, transport and handling capabilities, and many manufacturers can produce a variety of shapes and sizes upon request.

CASE STUDIES IN AUSTRALIA

Unlike CLT and even LVL beams, there are numerous examples of projects in Australia that have utilised glulam posts and beams in construction. The $2.5 million Equine Centre for the University of Ballarat and Riding for the Disabled Association Project is one example of glulam being used in public applications.

University of Ballarat Equine Centre. Image: H. Tron

Built by H. Troon, the project involved the construction of an 80 metre by 40 metre indoor riding arena, which was fully constructed from structural timber. Sourced from New Zealand, the glulam timber arches have a span of 40 metres.

Smith and Tracey Architects’ Olinda Tea House in Melbourne is another glulam application. The pavilion-style building with a floating butterfly roof was designed using post and beam glulam components from Laminated Timber Supplies. The main structural timbers included a mix of GL13 ‘A’ grade H-3 treated pine beams, cypress posts 7.5 metres high, and glulam columns spanning over 12 metres long.

The Olinda Tea House by Smith and Tracey Architects. Image: Smith and Tracey Architects

All the timber used in the project was double coated with Laminated Timber Supplies’ Cutek CD50 – a timber protection oil that aims to minimise warping, cupping and splitting of exterior woods.

WHERE TO GET YOUR LOCAL GLULAM FIX?

Glulam is manufactured widely in Australia, and manufacturers include Warrnambool Timber Industries, whose glulam beams utilise parts of Plantation Pine that would otherwise be discarded due to their shorter individual lengths.

The company then takes these shorter lengths to create longer beams, ensuring that no timber is left to waste during the manufacturing processes.

A durable and cost-effective solution, Warrnambool Timber Industries’ glulam can be used for applications ranging from a new home to a community barbeque shelter, an industrial shed to a public hall. It supplies its products to wholesalers such as Le Messurier, Dindas Australia and Laminated Timber Suppliers.

The latter’s Durabeam GL10 Cypress (F11), introduced over 20 years ago, is made from locally sourced Australian White Cypress. Available in lengths up to 18 metres, it has the highest durability rating available (durability class1), low and uniform shrinkage, and natural termite resistance so no treatment is required.

Featuring a hard wearing surface, making it suitable for both internal and external building applications, Durabeam GL10 has been produced to meet the GLTAA all relative Australian standards.

Hyne Timber’s Hyne Beam 17 is another glulam product on the market. Claiming to be the “strongest softwood glued laminated beam available”, the Plantation Pine glulam is suitable for numerous structural applications, particularly where high load and critical performance is required.

Produced from renewable resources, Hyne Beam 17 can be used for lintels over large window and door openings, garage beams, or as roof beams where spans over large spaces are dictated by design.